JPH0822693B2 - Conveyor using linear motor - Google Patents

Description

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a transfer device that transfers an object to be transferred using a linear motor.

(Prior Art) Recently, in a production line of a production factory, it has been desired to quickly and quietly convey an object to be conveyed from the viewpoint of improving production efficiency or improving a working environment. As such a transfer device, one using a linear motor including a linear motor coil and a reaction member is known. For example, as shown in FIG. 8, a transporting device using this linear motor includes one of linear motor coils b, b, ... , ...)
Are arranged along a roller conveyor e composed of a plurality of rollers d, d, ... As a stator, and the other (reaction member c in the figure) is used as a mover to be a pallet f which is an object to be conveyed.
Is attached to the mover (reaction member c) by the electromagnetic force between the linear motor coils b, b, ... And the reaction member c due to the thrust F generated in the mover (reaction member c). The pallet f and the one placed on the pallet f are conveyed via the.

In a control system of a transfer device using this linear motor, at least one of the position and speed of the pallet f during transfer is usually detected, as disclosed in, for example, Japanese Unexamined Patent Publication No. 56-141215. Based on the detection result, the operation of the linear motor a (more specifically, the amount of excitation of the linear motor coils b, b, ...) Is controlled so that the pallet f is conveyed in a predetermined manner.

(Problems to be Solved by the Invention) By the way, when the conveyed objects are sequentially fed to the plurality of work stations by using the linear motor, the conveyed objects that are adjacent to each other are conveyed at the same time, or the conveyed objects on the front side in the conveying direction are conveyed. If the conveyance of the objects to be transferred on the rear side is started during the conveyance, the distance between adjacent work staples is short and the speed of the objects to be conveyed is extremely high, so the objects to be conveyed collide. There is a risk of

On the other hand, in order to prevent the collision of such transported objects, after transporting the transported object on the front side, after confirming that the transported object does not exist in the transport area of the transported object on the rear side,
In some cases, the conveyance of the object to be conveyed on the rear side is started (see JP-A-60-237803). However, in this case, the conveyance delay of the front side conveyed object is accumulated in the conveyance of the rear side conveyed object, etc., so that the time required for conveyance in the entire production line becomes considerably long, and the conveyance efficiency and hence the production efficiency are There is a problem of being bad.

The present invention has been made in view of the above points, and an object of the present invention is to simultaneously convey adjacent objects to be conveyed, or to convey an object to be conveyed on the rear side while conveying an object to be conveyed on the front side in the conveying direction. When using the linear motor, the transport speed of the transported objects during transport can be appropriately changed to effectively prevent collision between the transported objects and improve transport efficiency. It is intended to provide a device.

(Means for Solving the Problems) In order to achieve the above object, the invention according to claim 1 is
In a transport device that sequentially feeds the transported objects to multiple work stations using a linear motor, transports the transported objects between adjacent work stations in the order of preset rising acceleration, constant speed transportation, deceleration stop A control means for controlling the operation of the linear motor, a position detection means for detecting that the object to be conveyed passes at least a constant speed conveyance transition position and a deceleration start position between adjacent work stations, and the position detection means. When the object to be conveyed on the front side in the conveying direction does not pass the constant speed conveyance transition position or the deceleration start position within the preset reference time, the conveying speed of the object to be conveyed on the rear side in the conveying direction is set in advance. It is configured to include a correction unit that corrects the control of the control unit so that the speed is lower than the set speed.

Here, the objects to be conveyed adjacent to each other are controlled so as to be simultaneously conveyed after the work at the work station is completed as in the invention according to claim 2, or the objects to be conveyed on the front side in the conveying direction as in the invention according to claim 3. It is controlled so as to start the conveyance of the object to be conveyed on the rear side during the conveyance.

(Operation) With the above configuration, in the present invention, based on the control of the control means for controlling the operation of the linear motor, the preset acceleration between the adjacent work stations of each transported object,
It is transported in the order of constant speed transportation and deceleration stop. During this conveyance, due to some reason, the conveyed object on the front side in the conveying direction abnormally approaches the conveyed object on the rear side without passing the constant speed conveyance transition position or the deceleration start position within the preset reference time. Then, this is detected by the position detection means, and the correction means corrects the control of the control means based on the detection result, so that the conveyance speed of the object to be conveyed on the rear side in the conveyance direction becomes lower than the preset speed. Will also be lower. As a result, the distance between the adjacent objects to be conveyed is maintained at a certain value or more, and collision between the objects to be conveyed is prevented.

(Example) Hereinafter, the Example of this invention is described based on drawing.

1 to 3 show a case where a carrier device A using a linear motor is applied to a vehicle assembly line as an embodiment of the present invention, and the carrier device A includes a pallet P as a material to be transferred. With the body B placed thereon, the work stations are conveyed between adjacent work stations in the order of rising acceleration, constant speed conveyance, deceleration stop, and within a fixed time. The pallet P is supported by a roller conveyor 3 composed of a large number of rollers 2, 2, ..., which are rotatably attached to supporting members 1, 1 on both sides of the conveyor line, and is conveyed while sliding on the roller conveyor 3. It is supposed to be done.

Inside the both supporting members 1, 1, for example, two stator rows 11, each of which is composed of a large number of linear motor coils 10, 10, ... As a stator formed by winding an excitation coil around a comb-teeth-shaped iron core, 11
Are juxtaposed. Two guide rails 12, 12 extending in the transport direction are arranged on both sides of each stator row 11 to guide a reaction member 14, which will be described later, along each stator row 11.

A first plate 13 is movably engaged with the guide rails 12, 12 on both sides of each of the stator rows 11, and the lower surface of the first plate 13 is made of, for example, iron or aluminum. A reaction member 14 as a mover, which is laminated in a circular shape, is integrally attached. Also,
A second plate 15 extending upward is integrally attached to the upper surface of the first plate 13, and the second plate 15 has a piston rod 16a extending forward in the transport direction (left side in FIG. 1). A cylinder 16 is arranged, and a cylinder member 17 is connected to the front end of the piston rod 16a of the front and rear cylinder 16. The cylindrical member 17 is a support shaft for the second plate 15.
An engaging projection member 19 provided on the back surface of the pallet P is supported inside the tubular member 17 so as to be rotatable around 18.
A base end portion of a rod 21 having an engaging block 20 that can be engaged with is fitted and supported on the rod 21, and a coil spring 22 is externally fitted on the rod 21. And each of the above stator rows
The reaction member 14 provided in 11 is moved to the front side in the transport direction along each stator row 11 by the thrust generated by the electromagnetic action between each stator row 11 and each linear motor coil 10. As a result, the pallet P is
With the engagement block 20 engaged with the engagement projection member 19, the body B on the pallet P is sequentially transported between adjacent work stations within a fixed time.
Therefore, the linear motor coil 10 and the reaction member
A linear motor 23 is constituted by 14 and one linear motor 23 is provided for each work station.

Here, after the pallet P, which is the object to be conveyed, is conveyed to the work station on the front side as described above, the rod 21 is rotated in the clockwise direction in FIG. As a result, the engaging projection member 19
The engaging block 20 is released from the engaged state and is retracted obliquely downward, and in this state, the reaction member 14 moving forward to the work station on the front side is moved backward to the work station on the rear side. There is. Further, when the pallet P moves over each roller 2 of the roller conveyor 3 due to the operation of the linear motor 23, a vertical fluctuation occurs, but this fluctuation is absorbed by the coil spring 22 fitted on the rod 21. This prevents the reaction member 14 from fluctuating in the vertical direction.

FIG. 4 shows a block configuration of a control unit for controlling the linear motor 23. In the figure, 31 is a speed detecting means composed of an encoder for detecting the transfer speed of the pallets P when the pallets P are transferred between adjacent work stations, 32
Is a position detecting means for detecting the current position of the pallet P when the pallet P is conveyed between adjacent work stations,
The reference numeral 33 indicates the operation of the linear motor 23 provided for each work station.
The controller 33 detects the conveyance speed of the pallet P between the corresponding work station and the work station on the front side (right side in the figure) in the conveyance direction. The signal from the speed detecting means 31 and the signal from the position detecting means 32 for detecting the current position of the pallet P between the work station on the front side in the conveyance direction of the corresponding work station and the work station on the front side of the corresponding work station are input. Has been done. Specifically, the position detecting means 32 includes three reflection tapes provided on the back surface of the pallet P as shown in FIG.
34, 34, 34 and three photosensors 36, 36, 36 provided on the supporting member 35 corresponding to the respective reflection tapes 34, and the light projected from each photosensor 36 is reflected by the reflection tape 34. When the pallet P is reflected by, it is detected that the pallet P has passed through the transport start position (acceleration start position), the constant speed transport transition position, and the deceleration start position.

Next, the control of the operation of the linear motor 23 by the controller 33 and the control of the conveyance of the pallet P will be described with reference to FIG. When the pallet P is conveyed between adjacent work stations, the controller 33 corresponding to the work station on the rear side in the conveyance direction corresponds to the front half of the conveyance, and the controller corresponding to the work station on the front side in the conveyance direction corresponds to the rear half of the conveyance direction. Transport of each pallet P by 33 (linear motor
The operation of 23) is controlled, but the control flow shown in FIG. 6 shows, as a series of controls, the control of transporting the pallet P between the adjacent work stations by the pair of controllers 33, 33 for convenience sake.

In FIG. 6, first, in step S1, a predetermined time has elapsed since the A1 signal from the position detecting means 32 indicating that the pallet P on the front side in the transport direction (hereinafter referred to as the front pallet) P is at the transport start position is received. After the lapse of time, the linear motor 23 is operated to start the conveyance of the pallet P with a constant acceleration, and the counter i is set to "0". Then
In step S2, it is determined whether or not the B1 signal from the position detecting means 32, which indicates that the front pallet P is in the constant speed transfer transition position, is input within the reference time. If this determination is YES, the conveyance speed of the pallet P is controlled based on the speed setting value preset in step S3. This control continues conveyance at a constant acceleration for a predetermined time after the B1 signal is input,
After that, it is conveyed at a constant speed.

Then, after setting the counter j to "0" in step S4, it is determined in step S5 whether the C1 signal from the position detecting means 32 that the front pallet P is at the deceleration start position is input within the reference time. To judge. When this determination is YES, the conveyance speed of the pallet P is controlled based on the speed setting value preset in step S6. In this control, the conveyance at a constant speed is continued for a predetermined time after the C1 signal is input, and thereafter the conveyance is performed at a constant deceleration.

Then, when the pallet P is transported to a predetermined position in the work station on the front side in the transport direction and the transport speed becomes zero, the operation of the linear motor 23 is stopped in step S7. As described above, when the front pallet P is normally transported in a predetermined manner, the transport control of the subsequent pallet P is completed. The mutual relationship between the conveying speeds of the front and rear pallets P, P and each signal of the position detecting means 33 at this time is shown in FIG. 7A. As can be clearly seen from this figure, the conveying speed v2 of the rear pallet P (lower part of the figure) v2 changes with a delay of a predetermined time with respect to the conveying speed v1 of the front pallet P (upper part of the figure) v1. Each pallet P is conveyed in the order of rising acceleration, constant speed conveyance, and deceleration stop.

On the other hand, when the determination in step S2 is NO, that is, when the conveyance of the front pallet P is delayed and the B1 signal from the position detection means 32 is not input within the reference time, the conveyance speed of the pallet P is set to 10 in step S8. % Slow down. Next, after counting up the counter i in step S9, step S1
At 0, it is determined whether the counter i is 4 or more. If this determination is NO, it is determined in step S11 whether or not the B1 signal is currently input, and if the determination is YES,
After the transport speed of the pallet P is returned to the original speed in step S12, the process proceeds to step S3. On the other hand, if the determination in step S11 is NO, the process returns to step S8. Also, step S1
When the judgment at 0 is YES, that is, when the count i is 4 or more, B1
When the input of the signal is considerably delayed, it is determined that an abnormality has occurred in the transport device, the transport speed is decelerated in step S13, and when the transport speed becomes zero, the operation of the linear motor 23 is stopped in step S14. Conveyance speed of both front and rear pallets P, when the B1 signal is input with a delay and position detection means 3
The mutual relationship with each signal of 3 is shown in FIG. 7B.

Further, when the determination in step S5 is NO, that is, when the conveyance of the front pallet P is delayed and the C1 signal from the position detecting means 32 is not input within the reference time, step S15
The pallet P transport speed is reduced by 10%. Next, after counting up the counter j in step S16, it is determined in step S17 whether the counter j is 4 or more.
If this determination is NO, it is determined in step S18 whether or not the C1 signal is currently input. If the determination is YES, the pallet P is stopped at a predetermined position of the work station on the front side in the transport direction in step S19. After performing the deceleration setting calculation for the above, in step 20, the conveyance speed of the pallet P is decelerated by the deceleration calculated by the calculation. Then, when the pallet P is transported to a predetermined position of the work station on the front side in the transport direction and the transport speed becomes zero, the step
The operation of the linear motor 23 is stopped in S21.

On the other hand, when the determination in step S18 is NO, the process returns to step S15. Further, when the determination in step S17 is YES, that is, when the count j is 4 or more and the input of the C1 signal is considerably delayed, it is determined that an abnormality has occurred in the transport device, and the transport speed is reduced in step S22, and the transport is performed. When the speed becomes zero, the operation of the linear motor 23 is stopped in step S23. FIG. 7C shows the mutual relationship between the conveying speeds of the front and rear pallets P, P and the signals of the position detecting means 33 when the C1 signal is input with a delay.

As described above, when the B1 signal is input with a delay, a series of steps S2, S8 to S for reducing the conveying speed of the rear pallet P are carried out.
14 and a series of steps S5, S15 to S2 for decelerating the conveyance speed of the rear pallet P when the C1 signal is input with a delay.
According to 3, when the front pallet P does not pass the constant speed transport transition position or the deceleration start position within the preset reference time, the transport speed of the rear pallet P is made 10% lower than the preset speed. Thus, the correction means 41 for correcting the normal control of the controller 33 is configured.

Therefore, in the above embodiment, the controller 33
On the basis of the control described above, since the rear pallet P is started to be transferred during the transfer of the front pallet P in the transfer direction, the time required for the transfer on the entire production line is shortened, and the transfer efficiency and thus the production efficiency are improved. Can be achieved. In addition, when the front and rear pallets P, P are conveyed at the same time, that is, when the front and rear linear motors 23, 23 start up at the same time, a very large amount of power is not consumed at one time, so the power consumption You can save money.

Further, during the transportation of the rear pallet P, the front pallet P is delayed in transportation for some reason, and the position detecting means 32
When the B1 signal which means that the front pallet P has passed the constant speed conveyance transition position or the C1 signal which means that the front pallet P has passed the deceleration start position is not input to the controller 33 within each reference time, Rear pallet P
The transport speed of is reduced more than the preset speed, and the distance between the front and rear pallets P, P is maintained at a certain value or more.
It is possible to reliably prevent collision between the pallets P, P.

The present invention is not limited to the above embodiment,
It also includes various other modifications. For example, in the above-described embodiment, the present invention is applied to the case where the linear motor coil 10 is used as the stator and the reaction member 14 is used as the mover to configure the linear motor 23, but the present invention is not limited to this, and the linear motor coil 10 is used, for example. The linear motor 23 can be similarly applied to a case where the linear motor 23 is provided by providing the reaction member 14 along the transport line and forming a stator while being provided on the first plate 13 side to form a mover.

Further, in the above-described embodiment, the case where the transfer device A is applied to the vehicle assembly line is shown, but the present invention is not limited to this, and it is needless to say that the present invention can be applied to the case where another object is transferred.

(Effects of the Invention) As described above, according to the transfer device using the linear motor of the present invention, the distance between the two objects to be transferred is fixed by a constant value while the adjacent objects to be transferred are simultaneously or sequentially transferred. Since the above can be maintained, it is possible to improve the transfer efficiency and prevent collision between the transferred objects.

[Brief description of drawings]

1 to 7 show an embodiment of the present invention. FIG. 1 is a side view of a conveying device, FIG. 2 is a plan view of the same, and FIG. 3 is a cross section taken along line III-III of FIG. 4 and 5 are block configuration diagrams of a control unit for controlling a linear motor, FIG. 5 is a schematic configuration diagram showing a configuration of position detecting means, FIG. 6 is a flow chart diagram showing a control flow, and FIG. 7 is adjacent. It is a figure which shows the mutual relationship of the conveyance speed of a pallet, and each signal of a position detection means. FIG. 8 is a view corresponding to FIG. 1 showing a conventional example. A: Transport device P: Pallet (transported object) 23: Linear motor 32: Position detection means 33: Controller (control means) 41: Correction means

Continuation of the front page (56) Reference JP-A 63-186506 (JP, A) JP-A 63-148803 (JP, A) JP-A 62-221804 (JP, A) JP-A 64-43006 (JP , A) JP 60-237803 (JP, A) JP 60-243706 (JP, A) JP 63-52607 (JP, A) JP 47-20814 (JP, A)

Claims (3)

[Claims] 1. A conveyance device for sequentially feeding an object to be conveyed to a plurality of work stations using a linear motor, wherein the object to be conveyed between adjacent work stations has preset rising acceleration, constant speed conveyance, and deceleration. Position detection that detects that the object to be conveyed passes at least the constant speed transfer transition position and the deceleration start position between the control means that controls the operation of the linear motor so that the objects are conveyed in the stop order and the adjacent work stations. Means and the signal from the position detecting means, and when the conveyed object on the front side in the conveying direction does not pass the constant speed conveying transition position or the deceleration start position within a preset reference time, the conveyed object on the rear side in the conveying direction is conveyed. A conveyance device using a linear motor, comprising: a correction unit that corrects the control of the control unit so that the conveyance speed of the object is lower than a preset speed. 2. A transfer device using a linear motor according to claim 1, wherein adjacent objects to be transferred are controlled so as to be transferred at the same time after the work at the work station is completed. 3. The linear motor according to claim 1, wherein adjacent objects to be conveyed are controlled so as to start the conveyance of the objects to the rear while the objects to be conveyed on the front side in the conveying direction are being conveyed. The transport device that was used.